Methods, apparatus and equipment for obtaining bound water saturation

Abstract

This application provides a method, apparatus, and device for obtaining bound water saturation. The method includes: acquiring reservoir parameters of a rock sample to be tested, and calculating the bound water saturation of the rock sample based on the reservoir parameters and a bound water saturation formula. The bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters, through multiple linear regression analysis. The bound water saturation of the multiple first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. Different cumulative permeability contribution rates are used to calculate the bound water saturation of different categories of rock samples, thereby ensuring the accuracy of the bound water saturation of the multiple first rock samples and the established bound water saturation formula. Therefore, the accurate bound water saturation of the rock sample to be tested can be obtained based on this formula.

Description

Technical Field

[0001] This application relates to the field of oil and gas exploration technology, and in particular to a method, apparatus and equipment for obtaining bound water saturation. Background Technology

[0002] With the development of petroleum exploration technology, oil and gas resource production has become increasingly stable. One of the important parameters in this field is bound water saturation. For example, in the exploration stage, accurate bound water saturation can improve the accuracy of fluid identification and reserve assessment. In the development stage, accurate bound water saturation helps in the identification of water-flooded layers and the determination of water-flood levels. Therefore, it is of great significance in production practice.

[0003] Currently, common methods for determining the bound water saturation of rock samples include core experiments, such as nuclear magnetic resonance logging, semi-permeable diaphragm methods, and mercury intrusion porosimetry. However, different rock samples vary and the situation is complex, so the accuracy of the bound water saturation obtained by these methods is not high. Therefore, obtaining accurate bound water saturation has become an urgent problem to be solved. Summary of the Invention

[0004] This application provides a method, apparatus, and device for obtaining bound water saturation, which is used to obtain accurate bound water saturation.

[0005] In a first aspect, embodiments of this application provide a method for obtaining bound water saturation, including:

[0006] Obtain reservoir parameters of the rock sample to be tested, including porosity, permeability and clay content;

[0007] Based on the reservoir parameters, the bound water saturation of the rock sample to be tested is calculated using the bound water saturation formula; wherein, the bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters through multiple linear regression analysis.

[0008] The bound water saturation of the plurality of first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. The cumulative permeability contribution rate corresponding to each category is determined based on the water saturation corresponding to that category and the relationship curve between water saturation and cumulative permeability contribution rate. The water saturation corresponding to each category is determined by nuclear magnetic resonance experiments, and the relationship curve corresponding to each category is obtained by mercury intrusion porosimetry experiments.

[0009] Furthermore, in the method described above, before calculating the bound water saturation of the rock sample to be tested based on the reservoir parameters and the bound water saturation formula, the method further includes:

[0010] Based on porosity and pore structure index, multiple second rock samples are classified into multiple categories, and the water saturation corresponding to the multiple categories is determined by nuclear magnetic resonance experiments; wherein, the water saturation corresponding to each category is one of the water saturation of the second rock sample corresponding to that category;

[0011] The first cumulative permeability contribution rate and the first water saturation of the multiple first rock samples were obtained by mercury intrusion porosimetry.

[0012] Based on the porosity and pore structure index of multiple first rock samples, the category to which the multiple first rock samples belong is determined; for each category, based on the first cumulative permeability contribution rate and the first water saturation of the first rock samples in that category, a corresponding relationship curve for that category is established;

[0013] Based on the category to which each first rock sample belongs, the second cumulative permeability contribution rate of the first rock sample is determined by finding the corresponding relationship curve for that category; wherein, the second cumulative permeability contribution rate of the first rock sample is the cumulative permeability contribution rate corresponding to the water saturation level of the category to which the first rock sample belongs;

[0014] The bound water saturation of the multiple first rock samples is calculated based on the second cumulative permeability contribution rate of the multiple first rock samples.

[0015] Obtain the reservoir parameters of the plurality of first rock samples;

[0016] Multiple linear regression analysis was performed on the bound water saturation and reservoir parameters, and relevant constants were determined by substituting the reservoir parameters and bound water saturation of the multiple first rock samples to establish the bound water saturation formula.

[0017] Furthermore, according to the method described above, the formula for the bound water saturation is:

[0018]

[0019] Among them, S wi V represents the bound water saturation, A1, A2, A3, and A4 are relevant constants, and V sh θ represents the clay content, K represents the permeability, and θ represents the porosity.

[0020] Furthermore, in the method described above, the classification of multiple second rock samples based on porosity and pore structure index yields multiple categories, including:

[0021] Porosity and permeability of multiple second rock samples were obtained;

[0022] Based on the porosity and permeability of the plurality of second rock samples, the pore structure index of the plurality of second rock samples is calculated.

[0023] The multiple second rock samples are classified according to their porosity and pore structure index.

[0024] Further, as described above, obtaining the first cumulative permeability contribution rate and the first water saturation of the plurality of first rock samples through mercury intrusion porosimetry includes:

[0025] Mercury intrusion porosimetry (MIRP) was used to establish the capillary curves of the multiple first rock samples.

[0026] Based on the mercury injection capillary curves, and using Purcell's formula, the first cumulative permeability contribution rate of the multiple first rock samples was calculated.

[0027] The formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the multiple first rock samples were obtained by measurement, and the first water saturation of the multiple first rock samples was calculated based on Archie's formula.

[0028] Furthermore, in the method described above, after calculating the bound water saturation of the rock sample to be tested based on the reservoir parameters and the bound water saturation formula, the method further includes:

[0029] The water saturation of the rock sample is calculated based on the formation resistivity, formation water resistivity, porosity, and rock electrical parameters.

[0030] Based on the bound water saturation and water saturation of the rock sample, the reservoir fluid of the reservoir in which the rock sample is located is identified.

[0031] Further, in the method described above, the step of identifying the reservoir fluid in the reservoir where the rock sample is located based on the bound water saturation and the water saturation of the rock sample includes:

[0032] If the water saturation of the rock sample to be tested is equal to the bound water saturation of the rock sample to be tested, then the reservoir fluid is identified as a gas layer.

[0033] If the water saturation of the rock sample to be tested is greater than the bound water saturation of the rock sample to be tested, then the reservoir fluid is identified as an aquifer.

[0034] Furthermore, in the method described above, after identifying the reservoir fluids in the reservoir where the rock sample is located based on the bound water saturation and the water saturation of the rock sample, the method further includes:

[0035] Output the identification results of the reservoir fluid.

[0036] Secondly, embodiments of this application provide a device for obtaining bound water saturation, comprising:

[0037] The acquisition module is used to acquire reservoir parameters of the rock sample to be tested, including porosity, permeability and clay content;

[0038] The calculation module is used to calculate the bound water saturation of the rock sample to be tested based on the reservoir parameters and the bound water saturation formula; wherein the bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters through multiple linear regression analysis.

[0039] The bound water saturation of the plurality of first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. The cumulative permeability contribution rate corresponding to each category is determined based on the water saturation corresponding to that category and the relationship curve between water saturation and cumulative permeability contribution rate. The water saturation corresponding to each category is determined by nuclear magnetic resonance experiments, and the relationship curve corresponding to each category is obtained by mercury intrusion porosimetry experiments.

[0040] Thirdly, embodiments of this application provide an electronic device, including: a memory and a processor;

[0041] Memory: Memory used to store the processor's executable instructions;

[0042] The processor is used to call program instructions in the memory to execute the bound water saturation acquisition method as described in the first aspect.

[0043] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the bound water saturation acquisition method as described in the first aspect.

[0044] Fifthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the bound water saturation acquisition method as described in the first aspect.

[0045] This application provides a method, apparatus, and device for obtaining bound water saturation. By acquiring reservoir parameters of a rock sample to be tested, and based on these parameters, the bound water saturation of the rock sample is calculated using a bound water saturation formula. The bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters, through multiple linear regression analysis. The bound water saturation of the multiple first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. In other words, in this embodiment, the correspondence between the rock category and the cumulative permeability contribution rate under porosity and pore structure index is obtained, and a bound water saturation formula is fitted based on the cumulative permeability contribution rate corresponding to the categories of multiple first rock samples. This formula takes into account the influence of rock category on the calculation of bound water saturation, thereby accurately obtaining the bound water saturation of the rock sample to be tested and avoiding the problem of low calculation accuracy due to differences in rock samples.

[0046] It should be understood that the content described in the foregoing summary section is not intended to limit the key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application.

[0048] Figure 1 A schematic diagram of a system architecture provided for this application;

[0049] Figure 2 A schematic diagram of the output result provided in this application;

[0050] Figure 3 A flowchart of the method for obtaining bound water saturation provided in this application;

[0051] Figure 4 A flowchart of the method for obtaining bound water saturation provided in this application;

[0052] Figure 5 A classification diagram of the second rock sample provided for this application;

[0053] Figure 6 The relationship curves between cumulative permeability contribution rate and water saturation under different categories provided in this application;

[0054] Figure 7 A flowchart of the method for obtaining bound water saturation provided in this application;

[0055] Figure 8 A schematic diagram of the bound water saturation acquisition device provided in this application;

[0056] Figure 9 A comparison of the bound water saturation determined based on the maximum mercury ingress pressure and the bound water saturation determined by NMR.

[0057] Figure 10 A comparison diagram of the bound water saturation determined by the method provided in this application and the bound water saturation determined by NMR.

[0058] Figure 11 This is a schematic diagram of the structure of the electronic device of this application. Detailed Implementation

[0059] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0060] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0061] With technological innovation and development, oil and gas resource production has become increasingly stable. Among the parameters, bound water saturation is one of the most important in this field and has significant implications for production practice. Currently, bound water saturation in rock samples is typically determined through nuclear magnetic resonance logging, semi-permeable baffle methods, mercury intrusion porosimetry, and other core experiments.

[0062] To address the aforementioned problems, this application provides a method, apparatus, and device for obtaining bound water saturation. The following embodiments illustrate the solution provided in this application.

[0063] Figure 1 A schematic diagram of a system architecture provided for this application, such as Figure 1 As shown, the Figure 1 The system architecture shown may specifically include a measuring device 1 and a server 2, wherein the server 2 is equipped with a device for obtaining bound water saturation.

[0064] The measuring device 1 can be any device capable of measuring reservoir parameters, and this embodiment is not limited thereto. The bound water saturation acquisition device can be mounted on a server to acquire the reservoir parameters of the rock sample to be tested sent by the measuring device, and calculate the bound water saturation of the rock sample to be tested based on the bound water saturation formula according to the reservoir parameters. The result can then be output by the server.

[0065] In practical applications, the type of output results can be determined according to user settings. For example, it may include, but is not limited to, reservoir parameters, bound water saturation, etc. In one example, Figure 2 An output result illustration provided for this application, such as Figure 2 As shown, the output results are presented in a list-like format, including: Column 1 is the formation channel, for example, the formation includes the following three formation segments: Bar-1, Bar-211, and Bar-212; Column 2 is the lithology curve channel for each formation segment, where CAL is the caliber curve, PE is the lithology curve, and GR is the natural gamma ray; Column 3 is the depth channel for each formation segment; Column 4 is the logging lithology channel; Column 5 is the logging interpretation channel; Column 6 is the resistivity curve channel, where M2RX is the 120-inch array inductive resistivity, M2R9 is the 90-inch array inductive resistivity, and M2R6 is the... The columns are: M2R1 (60-inch array induced resistivity), M2R2 (30-inch array induced resistivity), M2R3 (20-inch array induced resistivity), M2R1 (10-inch array induced resistivity). Column 7 is the physical property curve channel, where DEN is density, AC is acoustic transit time, and CNL is compensated neutron. Column 8 is the logging porosity, column 9 is the logging permeability, column 10 is the saturation curve channel, where SW is water saturation and SWI is bound water saturation. Column 11 is the gas logging channel, column 12 is the perforation channel, and column 13 is the oil testing results channel.

[0066] Example 1

[0067] Figure 3 The flowchart of the method for obtaining bound water saturation provided in this application is as follows: Figure 3 As shown, the method for obtaining bound water saturation provided in this embodiment includes the following steps:

[0068] Step 101: Obtain the reservoir parameters of the rock sample to be tested, including porosity, permeability and clay content.

[0069] Step 102: Based on the reservoir parameters and the bound water saturation formula, calculate the bound water saturation of the rock sample to be tested.

[0070] The bound water saturation formula is pre-established based on the bound water saturation and reservoir parameters of multiple first rock samples through multiple linear regression analysis. The bound water saturation of the multiple first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. The cumulative permeability contribution rate corresponding to each category is determined based on the water saturation corresponding to that category and the relationship curve between water saturation and cumulative permeability contribution rate. The water saturation corresponding to each category is determined by nuclear magnetic resonance (NMR) experiments, and the relationship curves corresponding to each category are obtained by mercury intrusion porosimetry (MIL) experiments.

[0071] It should be noted that the execution subject of the bound water saturation acquisition method provided in this embodiment can be a bound water saturation acquisition device. In practical applications, this bound water saturation acquisition device can be implemented by a computer program, such as application software or computer programs, or by a medium storing the relevant computer program, such as a USB flash drive or optical disc; or it can be implemented by a physical device that integrates or installs the relevant computer program, such as a chip.

[0072] In this embodiment, to obtain the bound water saturation of the rock sample to be tested, it is necessary to calculate the bound water saturation of the rock sample based on the bound water saturation formula. Specifically, the bound water saturation acquisition device first acquires the reservoir parameters of the rock sample to be tested. In practice, the reservoir parameters of the rock sample to be tested can be obtained by measuring equipment. After the measuring equipment obtains the reservoir parameters of the rock sample to be tested, it can be directly sent to the bound water saturation acquisition device, or it can be stored in a corresponding database for the bound water saturation acquisition device to retrieve. This embodiment does not limit this. The reservoir parameters include porosity, permeability, and clay content. Then, the bound water saturation acquisition device can substitute the actual data of the reservoir parameters into the bound water saturation formula in this scheme to calculate the bound water saturation of the rock sample to be tested.

[0073] It should be noted that the bound water saturation formula in this scheme is pre-established based on the bound water saturation and reservoir parameters of multiple first rock samples through multiple linear regression analysis. The bound water saturation of multiple first rock samples is calculated according to the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. In other words, this application establishes the correspondence between rock category and cumulative permeability contribution rate under different porosity and pore structure indexes. Specifically, the cumulative permeability contribution rate corresponding to each category is determined based on the water saturation corresponding to that category and the relationship curve between water saturation and cumulative permeability contribution rate. Among them, the first rock samples are mercury intrusion porosimetry (MIRP) rock samples, that is, the relationship curves corresponding to each category are obtained through mercury intrusion porosimetry experiments, and the specific method can be referred to relevant technologies. The water saturation corresponding to each category is determined by nuclear magnetic resonance (NMR) experiments, and the water saturation obtained by NMR experiments has high accuracy.

[0074] It is understood that this embodiment utilizes the high accuracy of nuclear magnetic resonance (NMR) experiments and the principle that rock samples of the same category have consistent water saturation. Based on the category to which the first rock sample belongs and the relationship curve between the water saturation and cumulative permeability contribution rate corresponding to that category, the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs is determined. Then, for each first rock sample, the bound water saturation is determined based on the cumulative permeability contribution rate. Specifically, bound water saturation is defined as follows: for a rock sample, the movable fluid and bound fluid can be distinguished based on the minimum pore throat radius of the rock sample. The fluid stored in pores smaller than the pore throat radius is the bound fluid, and the ratio of bound fluid to the total fluid in the pores is the bound water saturation. The minimum pore throat radius of the rock sample is determined based on the cumulative permeability contribution rate; specific methods can be found in related technologies. In other words, this scheme takes into account the dimensions of rock sample porosity and pore structure index when establishing the formula for bound water saturation. However, the bound water saturation calculation in related technologies does not take into account the influence of rock sample porosity and pore structure index. Therefore, the scheme of this application can avoid the problem of inaccurate calculation results caused by the differences between different rock samples and improve the accuracy of bound water saturation.

[0075] The bound water saturation acquisition method provided in this embodiment obtains the reservoir parameters of the rock sample to be tested, and calculates the bound water saturation of the rock sample based on the bound water saturation formula according to the reservoir parameters. The bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and the reservoir parameters through multiple linear regression analysis. The bound water saturation of the multiple first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. In other words, in this embodiment, based on the differences between different first rock samples, multiple first rock samples are classified using porosity and pore structure index. Different categories of rock samples use different cumulative permeability contribution rates to calculate the bound water saturation, thereby ensuring the accuracy of the bound water saturation of the multiple first rock samples, and thus ensuring the accuracy of the bound water saturation formula established based on the bound water saturation of the multiple first rock samples and the reservoir parameters. Therefore, the accurate bound water saturation of the rock sample to be tested can be obtained based on this bound water saturation formula.

[0076] Example 2

[0077] Figure 4 The flowchart of the method for obtaining bound water saturation provided in this application is as follows: Figure 4 As shown, the pore pressure prediction method provided in this embodiment, based on Embodiment 1 of this application, further includes the following steps before step 102:

[0078] Step 201: Based on porosity and pore structure index, classify multiple second rock samples to obtain multiple categories, and determine the water saturation corresponding to the multiple categories through nuclear magnetic resonance experiments; wherein, the water saturation corresponding to each category is one of the water saturation of the second rock sample corresponding to that category.

[0079] Step 202: Obtain the first cumulative permeability contribution rate and the first water saturation of the multiple first rock samples through mercury intrusion porosimetry.

[0080] Step 203: Determine the category to which the multiple first rock samples belong based on their porosity and pore structure index; for each category, establish the corresponding relationship curve based on the first cumulative permeability contribution rate and the first water saturation of the first rock samples in that category.

[0081] Step 204: Based on the category to which each first rock sample belongs, determine the second cumulative permeability contribution rate of the first rock sample by finding the corresponding relationship curve of that category; wherein, the second cumulative permeability contribution rate of the first rock sample is the cumulative permeability contribution rate corresponding to the water saturation of the category to which the first rock sample belongs.

[0082] Step 205: Calculate the irreducible water saturation of the multiple first rock samples based on the second cumulative permeability contribution rate of the multiple first rock samples.

[0083] Step 206: Obtain the reservoir parameters of the multiple first rock samples.

[0084] Step 207: Conduct a multiple linear regression analysis on the irreducible water saturation and reservoir parameters, and determine the relevant constants by substituting the reservoir parameters and irreducible water saturation of the multiple first rock samples to establish the irreducible water saturation formula.

[0085] In this embodiment, in order to establish the irreducible water saturation formula, the irreducible water saturation acquisition device can first classify multiple second rock samples based on porosity and pore structure index to obtain multiple categories, and determine the water saturation corresponding to each category through nuclear magnetic experiments. For example, multiple second rock samples can be classified using porosity and pore structure index to obtain three categories: Category I, Category II, and Category III. Among them, the water saturation corresponding to the second rock samples of Category I is A, the water saturation corresponding to the second rock samples of Category II is B, and the water saturation corresponding to the second rock samples of Category III is C. Here, the second rock samples are nuclear magnetic experiment rock samples.

[0086] It should be noted that since the water saturation corresponding to each second rock sample in each category is basically the same after classifying multiple second rock samples based on porosity and pore structure index, for each category, one second rock sample can be selected for nuclear magnetic measurement of water saturation to determine the water saturation corresponding to this category, and the experimental cost can be saved. That is to say, the water saturation corresponding to each category is one of the water saturations of the second rock samples corresponding to this category.

[0087] For example, Figure 5 is a schematic diagram of the classification of the second rock samples provided by this application. As Figure 5 shown, in practical applications, multiple second rock samples can be classified into three categories using porosity θ and pore structure index PTI. As Figure 5 shown is the relationship curve between time (unit: millisecond) and porosity component (unit: percentage). Among them, θ < 6%, PTI < 0.2 are the second rock samples of Category III, and the curve corresponding to them in the figure is the curve composed of ◆. 6% < θ < 9%, 0.2 < PTI < 0.26 are the second rock samples of Category II, and the curve corresponding to them in the figure is the curve composed of ■. θ > 9%, 0.26 < PTI are the second rock samples of Category I, and the curve corresponding to them in the figure is the curve composed of ▲). Among them, through nuclear magnetic experiments, the water saturation corresponding to the second rock samples of Category I is 55%, the water saturation corresponding to the second rock samples of Category II is 35%, and the water saturation corresponding to the second rock samples of Category III is 25%.

[0088] Next, the irreducible water saturation acquisition device can obtain the first cumulative permeability contribution rate and the first water saturation of multiple first rock samples to establish a relationship curve between the cumulative permeability contribution rate and the water saturation corresponding to different categories. Specifically, the first cumulative permeability contribution rate and the first water saturation of the multiple first rock samples can be obtained through mercury injection experiments.

[0089] Then, the irreducible water saturation acquisition device can determine the categories to which the multiple first rock samples belong based on the porosity and pore structure index of the multiple first rock samples. For example, Category I, Category II, or Category III. And for each category, based on the first cumulative permeability contribution rate and the first water saturation of the first rock samples under this category, a corresponding relationship curve is established. Next, according to the water saturation corresponding to the category to which each first rock sample belongs, by looking up the relationship curve corresponding to this category, the second cumulative permeability contribution rate of this first rock sample is determined. Among them, the second cumulative permeability contribution rate of the first rock sample is the cumulative permeability contribution rate corresponding to the water saturation corresponding to the category to which this first rock sample belongs.

[0090] Continuing with the above example, Figure 6 For the relationship curves between the cumulative permeability contribution rate and the water saturation under different categories provided by this application, as Figure 6 shown, in practical applications, the irreducible water saturation acquisition device can determine that the categories to which the multiple first rock samples belong are: Category III: θ < 6%, PTI < 0.2, Category II: 6% < θ < 9%, 0.2 < PTI < 0.26, Category I: θ > 9%, 0.26 < PTI based on the porosity and pore structure index of the multiple first rock samples. And based on the first cumulative permeability contribution rate and the first water saturation of the first rock samples under these Category I, II, and III, relationship curves corresponding to Category I, II, and III are respectively established, that is, the curves composed of ◆, ■, and ▲ shown in Figure 5 respectively. When looking up the relationship curve according to the water saturation corresponding to Category I, II, and III, if the first rock sample belongs to Category I, then look up the relationship curve corresponding to Category I, so as to determine that the second cumulative permeability contribution rate of this first rock sample is 99.999%. If the first rock sample belongs to Category II, then look up the relationship curve corresponding to Category II, so as to determine that the second cumulative permeability contribution rate of this first rock sample is 99.99%. If the first rock sample belongs to Category III, then look up the relationship curve corresponding to Category III, so as to determine that the second cumulative permeability contribution rate of this first rock sample is 99.9%.

[0091] Next, the irreducible water saturation acquisition device can calculate the irreducible water saturation of the multiple first rock samples by using a suitable method based on the second cumulative permeability contribution rate of the multiple first rock samples. The specific calculation method is not limited in this embodiment.

[0092] Finally, the bound water saturation acquisition device can acquire reservoir parameters from multiple first rock samples. Multiple linear regression analysis is then performed on the bound water saturation and reservoir parameters. By substituting the reservoir parameters and bound water saturation from multiple first rock samples, relevant constants are determined to establish a bound water saturation formula.

[0093] The bound water saturation acquisition method provided in this embodiment classifies multiple second rock samples based on porosity and pore structure index, and obtains the water saturation corresponding to multiple categories. Based on the porosity and pore structure index of multiple first rock samples, the category to which the multiple first rock samples belong is determined. By finding the first cumulative permeability contribution rate and the first water saturation of the first rock samples under that category, a relationship curve corresponding to that category is established to determine the second cumulative permeability contribution rate of the first rock sample, and then the bound water saturation of the multiple first rock samples is calculated. Furthermore, based on the bound water saturation of the multiple first rock samples and the obtained reservoir parameters of the first rock samples, a bound water saturation formula is established. In other words, in this embodiment, multiple second rock samples are classified based on porosity and pore structure index to obtain the water saturation corresponding to multiple categories. By combining the relationship curves between the first cumulative permeability contribution rate and the first water saturation of the first rock samples under different categories, the second cumulative permeability contribution rate of multiple first rock samples is determined, thereby obtaining the bound water saturation of multiple first rock samples and establishing a bound water saturation formula. This method comprehensively considers the differences between different first rock samples and uses the second cumulative permeability contribution rate of different first rock samples to calculate the bound water saturation of multiple first rock samples, which is more in line with the actual situation and effectively ensures the accuracy of the bound water saturation of the multiple first rock samples. Therefore, a more accurate bound water saturation formula can be established.

[0094] Based on the above embodiment two, the formula for bound water saturation is:

[0095]

[0096] Among them, S wi V represents the bound water saturation, A1, A2, A3, and A4 are relevant constants, and V sh θ represents the clay content, K represents the permeability, and θ represents the porosity.

[0097] For example, in practical applications, by substituting the reservoir parameters and bound water saturation of multiple first rock samples, the relevant constants A1 are determined to be 75, A2 to be 25.6, A3 to be 1.97, and A4 to be 1.1. The formula for bound water saturation is then:

[0098]

[0099] Among them, S wi To constrain water saturation, V shθ represents the clay content, K represents the permeability, and θ represents the porosity.

[0100] By using the above method, accurate relevant constants can be obtained, and a formula for bound water saturation can be established.

[0101] Based on the above embodiment 2, in order to further illustrate the method for obtaining bound water saturation of this application, in step 201, the classification of multiple second rock samples based on porosity and pore structure index to obtain multiple categories includes: obtaining the porosity and permeability of multiple second rock samples; calculating the pore structure index of the multiple second rock samples based on the porosity and permeability of the multiple second rock samples; and classifying the multiple second rock samples based on the porosity and pore structure index of the multiple second rock samples.

[0102] In this embodiment, in order to classify multiple second rock samples into multiple categories, the bound water saturation acquisition device can first acquire the porosity and permeability of the multiple second rock samples. Specifically, the porosity and permeability can be calculated using the density of the multiple second rock samples obtained by measurement, or they can be obtained by any other suitable method, which is not limited in this embodiment.

[0103] Next, the bound water saturation acquisition device can calculate the pore structure index of the multiple second rock samples based on their porosity and permeability. The specific calculation formula is as follows:

[0104]

[0105] Where PTI is the pore structure index, K is the permeability, and θ is the porosity.

[0106] Finally, the bound water saturation acquisition device can classify multiple second rock samples based on their porosity and pore structure index. The specific classification method has been described in the above embodiments and will not be repeated in this embodiment.

[0107] Using the above method, the pore structure index of multiple second rock samples can be calculated. Then, based on porosity and pore structure index, multiple second rock samples can be classified into multiple categories, which facilitates the calculation of bound water saturation using different cumulative permeability contribution rates for different categories of rock samples.

[0108] To further illustrate the method for obtaining the first water saturation of the first rock sample, based on the above-described Example 2, step 202 includes: establishing mercury intrusion porosimetry (MIP) capillary curves for the plurality of first rock samples through mercury intrusion porosimetry; calculating the first cumulative permeability contribution rate of the plurality of first rock samples based on the Purcell formula according to the mercury intrusion porosimetry capillary curves; obtaining the formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the plurality of first rock samples by measurement, and calculating the first water saturation of the plurality of first rock samples based on Archie's formula.

[0109] In this embodiment, to obtain the first cumulative permeability contribution rate of multiple first rock samples, the bound water saturation acquisition device first establishes mercury intrusion porosimetry (MIP) capillary curves for the multiple first rock samples through mercury intrusion porosimetry (MIP) experiments. Specifically, the horizontal axis of the MIP capillary curve represents the mercury injection rate, and the vertical axis represents the measurement pressure. Next, the bound water saturation acquisition device can calculate the first cumulative permeability contribution rate of the multiple first rock samples based on the Purcell formula, according to the MIP capillary curves. Specifically, the Purcell formula is:

[0110]

[0111] Where ∑K is the cumulative penetration rate contribution rate, in percentage (%), P i P i+1 These are the pressure points measured on the mercury intrusion porosimetry capillary curve, in MPa and ΔS. i-i+1 To measure pressure P i Pressurized to P i+1 Mercury ingress rate in the interval, in % K fi The percentage of permeability contribution between two pressure measurement points is expressed as %, and n is the number of permeability contribution rates.

[0112] Next, to obtain the first water saturation of multiple first rock samples, the bound water saturation acquisition device can measure the formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the multiple first rock samples, and calculate the first water saturation of the multiple first rock samples based on Archie's formula. Specifically, Archie's formula is:

[0113]

[0114] Among them, S w Water saturation is expressed as %, θ represents porosity, and R represents water content. w R is the resistivity of formation water. t The resistivity of the formation is measured in Ω·m, where a, b, m, and n are rock electrical parameters.

[0115] The method for obtaining bound water saturation provided in this embodiment calculates the first cumulative permeability contribution rate of multiple first rock samples based on Purcell's formula and the first water saturation of multiple first rock samples based on Archie's formula, thereby facilitating the subsequent establishment of a relationship curve based on the first cumulative permeability contribution rate and the first water saturation of the first rock sample.

[0116] Example 3

[0117] Figure 7 The flowchart of the method for obtaining bound water saturation provided in this application is as follows: Figure 7 As shown, the method for obtaining bound water saturation provided in this embodiment, based on any other embodiment, further includes the following steps after step 102:

[0118] Step 301: Calculate the water saturation of the rock sample based on the formation resistivity, formation water resistivity, porosity, and rock electrical parameters.

[0119] Step 302: Identify the reservoir fluid in the reservoir where the rock sample is located based on the bound water saturation and water saturation of the rock sample.

[0120] In this embodiment, in order to identify the reservoir fluids in the reservoir where the rock sample to be tested is located, after calculating the bound water saturation of the rock sample to be tested based on the bound water saturation formula according to the reservoir parameters, the bound water saturation acquisition device can calculate the water saturation of the rock sample to be tested based on the formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the rock sample to be tested. Specifically, the formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the rock sample to be tested can be obtained by measurement. In addition, the calculation method of the water saturation of the rock sample to be tested is the same as the calculation method of the first water saturation of the first rock sample in Embodiment 2, and will not be described again in this embodiment.

[0121] Next, the bound water saturation acquisition device can identify the reservoir fluid in the reservoir where the rock sample is located based on the bound water saturation and water saturation of the rock sample.

[0122] In one optional implementation, if the water saturation of the rock sample to be tested is equal to the bound water saturation of the rock sample to be tested, the reservoir fluid is identified as a gas layer; if the water saturation of the rock sample to be tested is greater than the bound water saturation of the rock sample to be tested, the reservoir fluid is identified as a water layer.

[0123] In this embodiment, the bound water saturation acquisition device compares the bound water saturation of the rock sample to its water saturation. Specifically, if the water saturation of the rock sample is equal to its bound water saturation, the reservoir fluid is identified as a gas layer. Conversely, if the water saturation of the rock sample is greater than its bound water saturation, the reservoir fluid is identified as a water layer. Figure 2 For example, Figure 2 The bound water saturation in the figure was calculated based on the scheme proposed in this application. Based on SW≈SWI (reflected in the layer with virtually no shadow area in the figure), the formation fluid is a gas layer; SW>SWI (reflected in the layer with shadow area in the figure), the formation fluid is a water layer. Therefore, the location at depth 6348m can be determined as the gas-water interface. During actual oil testing, the test results between 6270.5m and 6290.5m indicated a condensate gas layer, and the test results at 6401.89m indicated a water layer. The gas-water interface of the condensate gas layer and the water layer in this oil testing result is approximately between depths of 6290.5m and 6401.89m. The gas-water interface determined based on the bound water saturation is located at depth 6348m, falling within the aforementioned range. Therefore, the judgment result based on this scheme is consistent with the actual oil testing conclusion, thus proving the accuracy of the bound water saturation calculated based on the scheme proposed in this application.

[0124] Using the methods described above, based on the obtained bound water saturation, the reservoir fluids in the reservoir where the rock sample to be tested is located can be accurately identified, thereby providing a guarantee for the precise development of oil and gas reservoirs.

[0125] Based on the above embodiment three, in order to further illustrate the method for obtaining the bound water saturation of this application, after step 302, the method further includes: outputting the identification result of the reservoir fluid.

[0126] In practical applications, after the bound water saturation acquisition device identifies the reservoir fluid in the reservoir where the rock sample to be tested is located, it can output the identification result of the reservoir fluid for subsequent processing.

[0127] The bound water saturation acquisition method provided in this embodiment accurately identifies the reservoir fluid in the reservoir where the rock sample is located based on the bound water saturation and water saturation of the rock sample, and outputs the identification results, thereby providing a guarantee for the precise development of oil and gas reservoirs.

[0128] Example 4

[0129] Figure 8 This is a schematic diagram of the bound water saturation acquisition device provided in this application, as shown below. Figure 8As shown, the bound water saturation acquisition device provided in this embodiment includes an acquisition module 41 and a calculation module 42. The acquisition module 41 is used to acquire reservoir parameters of the rock sample to be tested, including porosity, permeability, and clay content. The calculation module 42 is used to calculate the bound water saturation of the rock sample to be tested based on the reservoir parameters and a bound water saturation formula. The bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters through multiple linear regression analysis. The bound water saturation of the multiple first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. The cumulative permeability contribution rate corresponding to each category is determined based on the water saturation corresponding to that category and the relationship curve between water saturation and cumulative permeability contribution rate. The water saturation corresponding to each category is determined by nuclear magnetic resonance (NMR) experiments, and the relationship curve corresponding to each category is obtained by mercury intrusion porosimetry (MIL) experiments.

[0130] The bound water saturation acquisition device provided in this embodiment acquires reservoir parameters of the rock sample to be tested, and calculates the bound water saturation of the rock sample based on the bound water saturation formula according to these reservoir parameters. The bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters through multiple linear regression analysis. The bound water saturation of the multiple first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. In other words, in this embodiment, based on the differences between different first rock samples, multiple first rock samples are classified using porosity and pore structure index. Different categories of rock samples use different cumulative permeability contribution rates to calculate the bound water saturation, thereby ensuring the accuracy of the bound water saturation of the multiple first rock samples, and thus ensuring the accuracy of the bound water saturation formula established based on the bound water saturation of the multiple first rock samples and reservoir parameters. Therefore, the accurate bound water saturation of the rock sample to be tested can be obtained based on this bound water saturation formula.

[0131] In an optional embodiment, the bound water saturation acquisition device further includes a determination module 43 and an establishment module 44. The determination module 43 is used to classify multiple second rock samples based on porosity and pore structure index to obtain multiple categories, and to determine the water saturation corresponding to each category through nuclear magnetic resonance (NMR) experiments; wherein the water saturation corresponding to each category is one of the water saturations of the second rock sample corresponding to that category. The acquisition module 41 is also used to obtain the first cumulative permeability contribution rate and the first water saturation of the multiple first rock samples through mercury intrusion porosimetry (MIL) experiments. The determination module 43 is also used to determine the category to which the multiple first rock samples belong based on their porosity and pore structure index; for each category, based on the first cumulative permeability contribution rate and the first water saturation of the first rock samples under that category, to establish a relationship curve corresponding to that category. The determining module 43 is further configured to determine the second cumulative permeability contribution rate of each first rock sample by finding the corresponding relationship curve for that category; wherein, the second cumulative permeability contribution rate of the first rock sample is the cumulative permeability contribution rate corresponding to the water saturation of the category to which the first rock sample belongs. The calculating module 42 is further configured to calculate the bound water saturation of the multiple first rock samples based on the second cumulative permeability contribution rates of the multiple first rock samples. The acquiring module 41 is further configured to acquire the reservoir parameters of the multiple first rock samples. The establishing module 44 is configured to perform multiple linear regression analysis on the bound water saturation and reservoir parameters, and determine the relevant constants by substituting the reservoir parameters and bound water saturation of the multiple first rock samples, so as to establish the bound water saturation formula.

[0132] In an optional embodiment, the formula for bound water saturation is:

[0133]

[0134] Among them, S wi V represents the bound water saturation, A1, A2, A3, and A4 are relevant constants, and V sh θ represents the clay content, K represents the permeability, and θ represents the porosity.

[0135] In an optional embodiment, the determining module 43 further includes: a first acquisition unit, a first calculation unit, and a first processing unit. The first acquisition unit is used to acquire the porosity and permeability of multiple second rock samples. The first calculation unit is used to calculate the pore structure index of the multiple second rock samples based on their porosity and permeability. The first processing unit is used to classify the multiple second rock samples based on their porosity and pore structure index.

[0136] In an optional embodiment, the acquisition module 41 further includes: an establishment unit, a second calculation unit, and a third calculation unit. The establishment unit is used to establish mercury intrusion porosimetry (MIP) capillary curves for the plurality of first rock samples through mercury intrusion porosimetry experiments. The second calculation unit is used to calculate the first cumulative permeability contribution rate of the plurality of first rock samples based on the mercury intrusion porosimetry capillary curves and Purcell's formula. The third calculation unit is used to obtain the formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the plurality of first rock samples through measurement, and calculate the first water saturation of the plurality of first rock samples based on Archie's formula.

[0137] In an optional embodiment, the calculation module 42 is further configured to calculate the water saturation of the rock sample based on the formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the rock sample. The bound water saturation acquisition device further includes an identification module 45. The identification module 45 is configured to identify the reservoir fluid in the reservoir where the rock sample is located based on the bound water saturation and the water saturation of the rock sample.

[0138] In an optional embodiment, the identification module 45 is further configured to: identify the reservoir fluid as a gas layer if the water saturation of the rock sample to be tested is equal to the bound water saturation of the rock sample to be tested; and identify the reservoir fluid as a water layer if the water saturation of the rock sample to be tested is greater than the bound water saturation of the rock sample to be tested.

[0139] It should be noted that the technical solution and effects of the bound water saturation acquisition device provided in this embodiment can be found in the relevant content of the foregoing method embodiments, and will not be repeated here.

[0140] Furthermore, in related techniques, the bound water saturation used to fit the bound water saturation formula is determined based on the maximum mercury ingress pressure of the mercury intrusion capillary curve; this is defined here as mercury intrusion bound water. Specifically, the cumulative permeability contribution rate of multiple rock samples is obtained through mercury intrusion experiments, and then, based on experience with rock samples from the region, one cumulative permeability contribution rate is selected to determine the bound water saturation. This method is inaccurate. For example, Figure 9 The image shows a comparison between the bound water saturation determined based on the maximum mercury ingress pressure and the bound water saturation determined by NMR. Figure 9As shown, ◆ represents the bound water saturation determined based on the maximum mercury intrusion pressure (mercury intrusion porosimetry bound water), and ■ represents the nuclear magnetic resonance (NMR) bound water saturation (NMR bound water), i.e., the bound water saturation determined by NMR experiments. This method yields highly accurate bound water saturation and can therefore be used as standard data for comparison. The comparison results show that the bound water saturation determined by mercury intrusion porosimetry differs significantly from that determined by NMR, and is therefore inaccurate. However, it should be noted that the drawback of NMR experiments is their high cost, thus limiting their practical application in exploration.

[0141] This application classifies multiple rock samples based on their differences, leveraging the high accuracy of nuclear magnetic resonance (NMR) experiments and considering porosity and pore structure indices. Different cumulative permeability contribution rates are used to calculate bound water saturation for different categories of rock samples, thus ensuring the accuracy of the bound water saturation calculation. For example, Figure 10 The image shows a comparison between the bound water saturation determined by the method provided in this application and the bound water saturation determined by NMR. Figure 10 As shown, ◆ represents the bound water saturation determined according to the scheme of this application, and ■ represents the bound water saturation determined by NMR. The comparison results show that the bound water saturation determined by the method provided in this application is basically consistent with the bound water saturation determined by NMR, and the accuracy is high. In other words, based on the scheme of this application, the data used to fit the bound water saturation formula is more accurate, and the bound water saturation formula obtained by fitting is also more reliable, thereby ensuring the accuracy of the bound water saturation result of the rock sample to be tested calculated based on the bound water saturation formula. Moreover, the calculation process does not require high-cost experiments, effectively saving costs.

[0142] Example 5

[0143] Figure 11 This is a schematic diagram of the structure of the electronic device of this application, as shown below. Figure 11 As shown, this application also provides an electronic device 500, including: a memory 501 and a processor 502.

[0144] Memory 501 is used to store programs. Specifically, the program may include program code, which includes computer-executable instructions. Memory 501 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0145] Processor 502 is used to execute programs stored in memory 501.

[0146] The computer program is stored in memory 501 and configured to be executed by processor 502 to implement the bound water saturation acquisition method provided in any embodiment of this application. Related descriptions can be understood by referring to the relevant descriptions and effects corresponding to the steps in the accompanying drawings, and will not be elaborated upon here.

[0147] In this embodiment, the memory 501 and the processor 502 are connected via a bus. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 11 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0148] Example 6

[0149] This application also provides a computer-readable storage medium storing a computer program thereon, which is executed by a processor to implement the method for obtaining bound water saturation provided in any embodiment of this application.

[0150] Example 7

[0151] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the method for obtaining bound water saturation provided in any embodiment of this application.

[0152] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0153] The modules described as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0154] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated module can be implemented in hardware or in a combination of hardware and software functional modules.

[0155] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to the processor or controller of a general-purpose computer, special-purpose computer, or other programmable bound water saturation acquisition device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0156] In the context of this application, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0157] Furthermore, although the operations are described in a specific order, this should be understood as requiring that such operations be performed in the specific order shown or in sequential order, or requiring that all illustrated operations be performed to achieve the desired result. In certain environments, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this application. Certain features described in the context of individual embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations.

[0158] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

Claims

1. A method for obtaining bound water saturation, characterized in that, include: Obtain reservoir parameters of the rock sample to be tested, including porosity, permeability and clay content; Based on the reservoir parameters, the bound water saturation of the rock sample to be tested is calculated using the bound water saturation formula; wherein, the bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters through multiple linear regression analysis. The bound water saturation of the plurality of first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. The cumulative permeability contribution rate corresponding to each category is determined based on the water saturation corresponding to that category and the relationship curve between water saturation and cumulative permeability contribution rate. The water saturation corresponding to each category is determined by nuclear magnetic resonance experiments, and the relationship curve corresponding to each category is obtained by mercury intrusion porosimetry experiments.

2. The method according to claim 1, characterized in that, Before calculating the bound water saturation of the rock sample based on the reservoir parameters and the bound water saturation formula, the method further includes: Based on porosity and pore structure index, multiple second rock samples are classified into multiple categories, and the water saturation corresponding to the multiple categories is determined by nuclear magnetic resonance experiments; wherein, the water saturation corresponding to each category is one of the water saturation of the second rock sample corresponding to that category; The first cumulative permeability contribution rate and the first water saturation of the multiple first rock samples were obtained by mercury intrusion porosimetry. Based on the porosity and pore structure index of multiple first rock samples, the category to which the multiple first rock samples belong is determined; for each category, based on the first cumulative permeability contribution rate and the first water saturation of the first rock samples in that category, a corresponding relationship curve for that category is established; Based on the category to which each first rock sample belongs, the second cumulative permeability contribution rate of the first rock sample is determined by finding the corresponding relationship curve for that category; wherein, the second cumulative permeability contribution rate of the first rock sample is the cumulative permeability contribution rate corresponding to the water saturation level of the category to which the first rock sample belongs; The bound water saturation of the multiple first rock samples is calculated based on the second cumulative permeability contribution rate of the multiple first rock samples. Obtain the reservoir parameters of the plurality of first rock samples; Multiple linear regression analysis was performed on the bound water saturation and reservoir parameters, and relevant constants were determined by substituting the reservoir parameters and bound water saturation of the multiple first rock samples to establish the bound water saturation formula.

3. The method according to claim 2, characterized in that, The formula for the bound water saturation is: Among them, S wi V represents the bound water saturation, A1, A2, A3, and A4 are relevant constants, and V sh θ represents the clay content, K represents the permeability, and θ represents the porosity.

4. The method according to claim 2, characterized in that, The classification of multiple second rock samples based on porosity and pore structure index yields multiple categories, including: Porosity and permeability of multiple second rock samples were obtained; Based on the porosity and permeability of the plurality of second rock samples, the pore structure index of the plurality of second rock samples is calculated. The multiple second rock samples are classified according to their porosity and pore structure index.

5. The method according to claim 2, characterized in that, The process of obtaining the first cumulative permeability contribution rate and first water saturation of the multiple first rock samples through mercury intrusion porosimetry includes: Mercury intrusion porosimetry (MIRP) was used to establish the capillary curves of the multiple first rock samples. Based on the mercury injection capillary curves, and using Purcell's formula, the first cumulative permeability contribution rate of the multiple first rock samples was calculated. The formation resistivity, formation water resistivity, porosity, and rock electrical parameters of the multiple first rock samples were obtained by measurement, and the first water saturation of the multiple first rock samples was calculated based on Archie's formula.

6. The method according to any one of claims 1-5, characterized in that, After calculating the bound water saturation of the rock sample based on the reservoir parameters and the bound water saturation formula, the method further includes: The water saturation of the rock sample is calculated based on the formation resistivity, formation water resistivity, porosity, and rock electrical parameters. Based on the bound water saturation and water saturation of the rock sample, the reservoir fluid of the reservoir in which the rock sample is located is identified.

7. The method according to claim 6, characterized in that, The step of identifying reservoir fluids in the reservoir where the rock sample is located based on the bound water saturation and the water saturation of the rock sample includes: If the water saturation of the rock sample to be tested is equal to the bound water saturation of the rock sample to be tested, then the reservoir fluid is identified as a gas layer. If the water saturation of the rock sample to be tested is greater than the bound water saturation of the rock sample to be tested, then the reservoir fluid is identified as an aquifer.

8. The method according to claim 7, characterized in that, After identifying the reservoir fluids in the reservoir where the rock sample is located based on the bound water saturation and the water saturation of the rock sample, the method further includes: Output the identification results of the reservoir fluid.

9. A device for obtaining the saturation of bound water, characterized in that, include: The acquisition module is used to acquire reservoir parameters of the rock sample to be tested, including porosity, permeability and clay content; The calculation module is used to calculate the bound water saturation of the rock sample to be tested based on the reservoir parameters and the bound water saturation formula; wherein the bound water saturation formula is pre-established based on the bound water saturation of multiple first rock samples and reservoir parameters through multiple linear regression analysis. The bound water saturation of the plurality of first rock samples is calculated based on the cumulative permeability contribution rate corresponding to the category to which the first rock sample belongs under porosity and pore structure index. The cumulative permeability contribution rate corresponding to each category is determined based on the water saturation corresponding to that category and the relationship curve between water saturation and cumulative permeability contribution rate. The water saturation corresponding to each category is determined by nuclear magnetic resonance experiments, and the relationship curve corresponding to each category is obtained by mercury intrusion porosimetry experiments.

10. An electronic device, characterized in that, include: Memory, processor; Memory: Memory used to store the processor's executable instructions; The processor is used to call program instructions in the memory to execute the method for obtaining bound water saturation as described in any one of claims 1-8.

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